Stored program controlled communication switching systems comprise some form of intelligence which controls switching functions in response to a program stored in memory. Historically, such systems included a single processing entity which controlled the entire communication path between subscribers to a telephone office. As technology and system design evolved, it was found desirable to separate certain routine functions from the main processing entity to save its processing time for more complex system functions and decisions. Systems, called distributed control systems, are presently being designed which also separate the control of portions of a communication path into several intelligent processors.
Before subscribers are connected to the communication path through a telephone switching system, checks should be performed to establish that the communication path is continuous. When all portions of the communication path are controlled by a single entity, such checks are relatively easy since all the necessary information is available in the single control entity. Such checks become quite difficult and time consuming when multiple control entities are used and each control entity must check what the others have done.
It is the object of the present invention to provide a quick and reliable arrangement for checking communication path continuity through a time divided communication path which is controlled by more than one control processor.